1. Field of the Invention
The invention relates to a positioning system, more particularly to a positioning system for a movable object.
2. Description of the Related Art
At present, some vehicle security systems, such as those disclosed in R.O.C. Patent Publication No. 413366 and R.O.C. Patent No. I246481, are integrated with satellite-based positioning systems so that vehicle owners are able to monitor the location of their vehicles at any time. Such vehicle security systems include a server, and a positioning terminal disposed on a vehicle and capable of receiving satellite-transmitted signals and detecting status of the vehicle. The satellite-transmitted signals are decoded to result in positioning data (i.e., coordinate data) sent to the server. In addition, when an abnormal status of the vehicle is detected, such as when an intruder is detected or when the vehicle is towed, the server is able to notify the vehicle owner immediately by telephone so that the vehicle owner may act accordingly.
However, the aforementioned vehicle security systems require storage of detailed information and contact data of vehicle owners in the server. Hence, if the server is hacked, the detailed information and contact data of the vehicle owners can be stolen, and the locations of their vehicles will be revealed to the hacker. As a result, privacy and security of confidential information are not ensured.